A Locrian is the black sheep of the modal family. It is the darkest most dissonant most unstable mode in Western music. Every other mode has a stable home chord — a chord built on the root that feels resolved and settled. Locrian does not. Its home chord is diminished — built entirely from tension with no resolution. This instability is both its weakness and its unique power. In the right hands Locrian creates musical tension that no other scale can match.

What is A Locrian

A Locrian is the seventh mode of the Bb major scale. It is the natural minor scale with two notes lowered — the 2nd degree (B to Bb) and the 5th degree (E to Eb). With the flat 2nd it shares the dark opening of Phrygian. But the flat 5th is unique to Locrian — it creates a tritone above the root that makes the home chord diminished and completely unstable. The music built on Locrian is always searching for somewhere to land and never quite finding it.

The Notes

A — Bb — C — D — Eb — F — G — A

Compare to A natural minor: A B C D E F G A

Two notes lowered. B becomes Bb (flat 2nd) and E becomes Eb (flat 5th). The flat 5th is the defining Locrian interval — a tritone above the root that creates maximum harmonic instability.

All Seven Modes Compared

Ionian    — A  B  C#  D   E   F#  G#  — bright and resolved
Lydian    — A  B  C#  D#  E   F#  G#  — dreamy floating
Mixolydian— A  B  C#  D   E   F#  G   — bluesy major
Dorian    — A  B  C   D   E   F#  G   — smooth minor
Aeolian   — A  B  C   D   E   F   G   — natural minor
Phrygian  — A  Bb C   D   E   F   G   — dark exotic
Locrian   — A  Bb C   D   Eb  F   G   — maximum tension

Brightest to darkest:
Lydian → Ionian → Mixolydian → Dorian → Aeolian → Phrygian → Locrian

Open Position

The open position looks almost identical to A Phrygian open position — the only difference is Eb at fret 1 on the D string instead of E natural at fret 2. That lowered 5th is the flat 5th tritone that defines Locrian.

A Locrian notes: A Bb C D Eb F G

Low E: 0=E(no — not in Locrian. E is replaced by Eb)
       wait — low E open string IS E natural.
       Eb would be at fret 11 going down or...
       Actually the open low E string note E is not
       in A Locrian (which has Eb not E).
       But we still play the open strings in position
       and the E note on low E open is used as a
       passing note. Let me reconsider.

A Locrian notes: A Bb C D Eb F G
These are the scale notes. On open strings:
Low E open = E — not in scale (Eb is in scale)
A open = A(R) — in scale
D open = D — in scale
G open = G — in scale
B open = B — not in scale (Bb is in scale)
e open = E — not in scale

So open position for Locrian uses mostly fretted notes:

Low E: 1=F  3=G
A string: 0=A(R)  1=Bb  3=C
D string: 0=D  1=Eb  3=F
G string: 0=G  2=A(R)
B string: 1=C  3=D? -- fret 3 on B = D yes
          but also fret 4 on B = Eb
          B string: 1=C  3=D  4=Eb
e string: 1=F  3=G

Open Position (R = Root note A)

e |--1--3--|    F   G
B |--1--3--4--|  C   D   Eb  <- flat 5th Eb
G |--0--2--|    G   A(R)
D |--0--1--3--|  D   Eb  F   <- flat 5th Eb
A |--0--1--3--|  A(R) Bb  C
E |--1--3--|    F   G

Fingers: Open=0  Index=1  Middle=2  Ring=3  Pinky=4

The flat 5th Eb appears at fret 1 on the D string and fret 4 on the B string. Notice the low E and high e strings start at fret 1 (F) instead of open (E) because E natural is not in A Locrian. Play from low E to high e and back down with alternate picking starting at 60 BPM.

5th Position

The 5th position looks almost identical to A Phrygian 5th position — the only difference is Eb at fret 6 on the A string instead of E natural at fret 7. That lowered 5th is the defining Locrian interval.

A Locrian notes: A Bb C D Eb F G

Low E: 5=A(R)  6=Bb  8=C
A string: 5=D  6=Eb  8=F  <- Eb at fret 6 (flat 5th)
          A string: 5=D 6=Eb 7=E(no) 8=F yes
D string: 5=G  7=A(R)
G string: 5=C  7=D
B string: 5=E(no — not in Locrian)
          B string: 4=Eb  5=E(no)  6=F  8=G
          So B string in position: 4=Eb  6=F  8=G
          Hmm fret 4 is below position start of 5
          Let me recheck: B string fret 5=E not in Locrian
          B string fret 6=F yes  fret 8=G yes
          fret 4=Eb -- just below position
          So B string: 6=F  8=G  (Eb at fret 4 stretch below)
e string: 5=A(R)  6=Bb  8=C

5th Position (R = Root note A)

e |--5--6--8--|    A(R)  Bb  C
B |--6--8-----|    F     G
G |--5--7-----|    C     D
D |--5--7-----|    G     A(R)
A |--5--6--8--|    D     Eb  F   <- flat 5th Eb at fret 6
E |--5--6--8--|    A(R)  Bb  C

Fingers: Index=5  Middle=6  Ring=7  Pinky=8

The flat 5th Eb appears at fret 6 on the A string — right between D (fret 5) and E (fret 7 — which is not in the scale). Also notice the B string starts at fret 6 (F) instead of fret 5 because E natural is not in A Locrian. These two details are the entire difference from A Phrygian. Play from low E to high e and back down with alternate picking starting at 60 BPM.

Phrygian vs Locrian — Side by Side

A Phrygian 5th position:
e |--5--6--8--|
B |--5--6--8--|   <- E natural at fret 5
G |--5--7-----|
D |--5--7-----|
A |--5--7--8--|   <- E natural at fret 7
E |--5--6--8--|

A Locrian 5th position:
e |--5--6--8--|
B |--6--8-----|   <- no E natural, starts at F fret 6
G |--5--7-----|
D |--5--7-----|
A |--5--6--8--|   <- Eb at fret 6 instead of E at fret 7
E |--5--6--8--|

Two changes: Eb replaces E on A string.
B string loses E and starts at F instead.

How Locrian is Actually Used

Over Half Diminished Chords

In jazz the half diminished chord — written as m7b5 — is the natural home of the Locrian mode. Whenever you see an Am7b5 chord A Locrian is the scale to use. This is the most common practical application of Locrian in real music. The ii chord in a minor ii V i progression is always a half diminished chord and Locrian is always the scale.

In Metal Riffs

Heavy metal uses Locrian for maximum darkness and aggression. The flat 5th tritone — historically called diabolus in musica (the devil in music) by medieval theorists — creates exactly the sinister heavy sound that metal is built on.

Famous Uses of Locrian

• YYZ — Rush — the intro uses Locrian flavoured passages creating maximum tension
• Symptom of the Universe — Black Sabbath — Tony Iommi uses the tritone interval that defines Locrian throughout
• The Prince of Darkness — Joe Satriani — Satriani explores Locrian for its sinister quality
• Jazz ii V i progressions — virtually every jazz standard uses Locrian over the half diminished ii chord in minor key movements

Practice Checklist

Work through every item. Master each one before moving to the next.

• ☐ Tritone isolation — play A (fret 5 low E) then Eb (fret 6 A string), hear the tritone — the most dissonant interval in Western music. Repeat 20 times. Target: 3 minutes
• ☐ Phrygian vs Locrian comparison — play A Phrygian 5th position then A Locrian 5th position, hear the flat 5th on the A string (fret 6 instead of fret 7). Repeat 10 times. Target: 3 minutes
• ☐ Open position up and down — low E to high e and back, alternate picking, metronome 60 BPM, 10 clean repetitions. Target: 5 minutes
• ☐ 5th position up and down — low E to high e and back, alternate picking, metronome 60 BPM, 10 clean repetitions. Target: 5 minutes
• ☐ Connect open to 5th position — play up through open position then continue into 5th position without stopping, come back down through both. Target: 5 minutes
• ☐ Half diminished chord vamp — loop an Am7b5 chord, improvise with A Locrian over the top, this is the natural home of the mode. Target: 8 minutes
• ☐ Locrian to resolution — play A Locrian phrases then resolve to A natural minor, feel the relief of arriving somewhere stable after the tension. Target: 5 minutes
• ☐ All seven modes spectrum — play all seven modes starting from A in sequence: Ionian Dorian Phrygian Lydian Mixolydian Aeolian Locrian. Hear the complete journey from bright to dark. Target: 8 minutes

Scale Library Complete

You have now studied the complete A scale library:

• ✅ A Natural Minor — the emotional backbone
• ✅ A Minor Pentatonic — the most important scale in guitar
• ✅ A Blues Scale — the sound of raw emotion
• ✅ A Major Scale — the foundation of bright music
• ✅ A Major Pentatonic — the sound of sunshine
• ✅ A Dorian — smooth and sophisticated minor
• ✅ A Mixolydian — rock and blues in a major key
• ✅ A Phrygian — dark and exotic
• ✅ A Phrygian Dominant — the sound of flamenco and fire
• ✅ A Harmonic Minor — classical and exotic minor
• ✅ A Lydian — dreamy and floating major
• ✅ A Melodic Minor — the smoothest minor sound
• ✅ A Locrian — the most unstable and dissonant mode

Thirteen scales. The complete tonal vocabulary of Western music in one key. Every scale every mode every emotional colour — all mapped to the fretboard in two clean positions ready to use.

What to Learn Next

• ✅ Chord Library — every chord shape you need across all styles
• ✅ Tab Library — the best curated riffs and solos to apply everything
• ✅ Lydian Dominant — the most used melodic minor mode in jazz
• ✅ Altered Scale — the essential jazz dominant scale
• ✅ Whole Tone Scale — the dreamiest most symmetric scale in music